1. Field of the Invention
The present invention is related to a vehicular seatbelt and, more particularly, to a retractor for such a seatbelt, in which the winding and release prevention of a seatbelt about a spool of the retractor can be performed during an abnormal driving state (e.g., collision, or roll-over) of a vehicle.
2. Discussion of the Related Art
Generally, there has been a well-known technology in this field that a seatbelt retractor is asked to facilitate the webbing upon the wearing of the seatbelt by an occupant or to prevent the drawing-out of the webbing in an emergency or abnormal state of a vehicle. However, what is considered as a problem in this technical field is the timely detection of the abnormal state of the vehicle. To do so, a webbing sensor for detecting the pulling-out acceleration of the webbing and a motion (inertia) sensor for detecting the abnormal state of the vehicle during driving due to any sudden and/or severe disruption in traveling speed, due to the impact of a collision for example, have been developed to supplement their disadvantages to each other. Herein, it is noted that the pulling-out acceleration detection of the webbing, including its responding time, must comply with the counteracted against the abrupt rotation during running and the rollover in a slanted street and off-road conditions.
In respect of these points, a typical technology is U.S. Pat. No. 3,819,126 disclosing a seatbelt retractor with a gear wheel actuated locking means, which comprises a supporter, a reel means rotatably mounted on the side wall of the supporter, an elongated flexible seatbelt connected to the reel means, a bias means pressing the reel means in a winding direction and a locking member mounted on the reel means to be pivoted between a locking position for preventing the rotation of the reel in the unwinding direction and a pair of release positions for allowing the reel to be rotated in the unwinding direction.
Additionally, a clutch plate is slidably mounted between the side wall of the support and a ratchet and includes a conical spring mounted on the reel between the clutch plate and the support sidewall to urge the clutch plate toward frictional engagement with the ratchet. The clutch plate includes a first stop mounted on the reel to be arranged on the path of motion of the locking member. The first stop disables the locking member as the belt is being unwound from a fully wound position.
A disabling member is rotatably mounted on a pin carried on the end of the reel and includes a finger received in a slot in the support for limiting the rotational displacement, a resilient arm connected to the support to bias it in the winding direction, an arm having an enlargement connected through an opening of the locking member and ridges forming a cam of three protrusions spaced equidistantly about its center, so that it rotates through the reel as the first stop is being moved out of the path of motion of the locking member.
A wheel is rotatably mounted on the pin adjacent the disabling member and includes an annular series of regularly spaced teeth formed concentrically about the axis of rotation of the pins, a second stop constituted as a radial enlargement for engaging the locking member in its intermediate release position, a planar surface facing the disabling member, three rounded conical projections engaging the ridges and a resilient arm having a finger formed at its one end and received in an opening in the support to bias the wheel both toward the disabling member. The other end of the wheel has a foot for engaging a shoulder carried by the wheel to position the second stop to abut the locking member in its intermediate release position. The second stop disables the reel-locking device when the belt is rapidly released or unwounded from the retractor or the vehicle is in the abnormal state.
An actuator is mounted with a press fit on a pin adjacent the wheel and includes three resilient elongated pawls which are radially movable between inner and outer positions and a cylindrical shoulder rotatably supporting an inertia wheel. The inertia wheel carries three pins engaging the free ends of the pawls and has a mass selected such that it normally rotates with the actuator.
An inertia operated means is mounted adjacent the inertia wheel and includes a housing mounted on the support and a metal ball disposed in the housing to be movable on a conical base. A lever is pivotally mounted on a pin and includes a flag disposed in the opening in contact with the ball and a permanent magnet disposed adjacent the inertia wheel. The arrangement is such that when the reel is rotated in the unwinding direction by a pulling effort on the belt the inertia wheel rotates slightly with respect to the actuator to cause the pin to cam pawls radially outwardly to mate with the teeth. At that time, the wheel is connected to the reel so as to be rotated in the unwinding direction, and a
Therefore, as the reel is rotated rapidly in the unwinding direction by the pulling out on the belt, the inertia wheel rotates slightly with respect to the actuator to cause the pins to cam the pawls radially outwardly to mate with the teeth. The wheel is then connected to the reel so as to be rotated in the unwinding direction. A relatively small rotation of the second stop permits the locking member to be moved by the spring toward the ratchets and a locking position that prevents further unwinding of the belt.
In the abnormal state of the vehicle, the ball becomes unseated from the opening to permit the magnet of the lever to engage the inertia wheel and thereby actuate the pawls. At that time, the reel is rotated in the unwinding direction so that the pawl is engaged with the wheel, and the locking member is engaged with the ratchets, thereby preventing the further webbing of the belt.
In order to release the locking member from the ratchets, the small amount of the belt is wound on the reel to rotate the second stop in the winding direction so as to return the locking member to its immediate position. This motion of the reel in the winding direction also rotates the actuator with respect to the inertia wheel to return the pawls to their normal inner position.
However, the seatbelt retracting device has a disadvantage in that the clutch plate, the disabling member and the wheel are required so that the locking member engaged with the ratchets of the reel should be fixed on the normal position. For example, the clutch plate is mounted between the reel ratchet and the support to be biased by the spring so that the first stop supports the locking member in a pushing direction. The disabling member its resilient arm is connected to the support to be biased in the winding direction and the enlargement of the arm is fitted into the opening of the locking member to support the locking member in the unwinding direction. The wheel includes the resilient arm and the second stop, in which the resilient arm has a finger at the outer end to be supported in the opening of the support to bias the wheel toward the disabling member and has a foot for positioning the second stop to abut the locking member in its intermediate release position.
Therefore, in order to control the retracting and releasing of the webbing, the first stop of the clutch plate determines the position of the locking member, and the second stop of the wheel disables the locking member.
Such like seatbelt retracting device has a rapid response speed in detecting the webbing and a superior restraint force of an occupant during driving in an off-road environment. However, the inertia operated means constituted as a vehicle motion sensor has complex procedures in confining the operations of the reel or ratchets, cooperating with the inertia wheel. It causes fear that the rotation restraining of the reel may be retarded.
Another technology that resolves this advantage and prevents the releasing of the webbing at a rapid speed per international standards is U.S. Pat. No. 5,507,448 assigned to this Applicant.
A seatbelt retractor comprises a ratchet wheel rotated with respect to a spool, at least a pawl member for selectively braking the spool with respect to one of its rotation directions and a device for detecting the rotation amount of the spool and braking the ratchet wheel at over a predetermined rotation amount, thereby preventing the excessive releasing of the webbing. Herein, it is noted that one pawl is engaged with the ratchet wheel in response to the operation of the webbing sensor, and as a locking ring with a slot is rotated during the operating of that the webbing releasing preventing device, the pawl stops the ratchet wheel to prevent further release of the webbing.
The seatbelt retractor has a disadvantage in that it cannot meet with the rollover phenomena of a vehicle in an off-road environment, etc., because the webbing sensor is adjusted to have a predetermined response time to the vehicle""s abnormal state. In other words, the webbing restraining can be performed only after elapsing a predetermined delay time. It means that the seatbelt retractor allows some amount of the webbing releasing.
In light of these points, it is much preferable to respond to the operating of the webbing sensor at the same time and to supplement the advantages of a webbing sensor that overcomes the rollover phenomena in an off-road condition and the inertia sensor having a reliability in its operation to each another.
An object of the present invention is to provide a vehicular seatbelt retractor for performing the operations of detecting the releasing acceleration of the webbing and the abnormal state such as the colliding, simultaneously or selectively.
Another object of the present invention is to provide a vehicular seatbelt retractor for preventing the releasing of the webbing directly in response to the detection of the webbing acceleration.
Another object of the present invention is to provide a vehicular seatbelt retractor for preventing the releasing of the webbing directly in response to the detection of the vehicle""s abnormal state.
Still another object of the present invention is to provide a vehicular seatbelt retractor for preventing the releasing of the webbing in response to the detections of the webbing acceleration and the vehicle""s abnormal state at the same time or separately.
According to the present invention, a vehicular seatbelt retractor comprises a frame including openings formed at the center of each of foot portion, on the upper portion of which a frictional tooth portion is formed in a predetermined arc shape and a groove portion formed in a larger size than that of the opening of one foot portion and enlarged from one part of the circular arc of the opening; a spool including flanges extended in a circular arc from its both sides to be positioned on the thickness of the opening, a mounting block projected in a circular form from one side of one flange to have a smaller diameter than that of the flange and a sprocket integrally projected from one side of the other flange to be received in the groove portion; a receptacle including a first case enabling the movement of the mounting block therein and a second case receiving a spring therein; a retainer mounted at the one side adjacent the sprocket by means of a spring and including a retainer ring formed on the other side inside the circumferential portion thereof with a second sprocket formed around its inner circumference and a hook ring formed at a predetermined position of its circumference to cooperate with a guide element of a locking element; a mass member in the form of a circular body including at least one wing extended in a semi-circular arc shape from its diameter line with a latch formed at its free end and hooks projected in a predetermined distance to each another from the front side thereof; a clutch wheel including a first tooth portion formed on the inner thickness portion of an opening at its center to couple with the mass member, a coupling surface formed at its outer surface to couple with the hooks and a second tooth portion formed around the circumference thereof; and a pawl device including a housing, a standing weight including a first permanent magnet mounted on the upper portion thereof and for being able to be inclined in the housing and a pawl level mounted on the upper portion of the housing and including a second permanent magnet positioned to face at the same pole to the first permanent magnet.
The vehicular seatbelt retractor further comprises a webbing control device including the locking element cooperated with the sprocket of the spool, the retainer enabling the locking element to perform the movement of a pendulum, the mass member received in the retainer to enable at least one its latch to transfer its rotational force to the retainer and the clutch wheel enabling the wing latch to be contacted with the first tooth portion when coupled with the mass member and to be passed over the saw top of the first tooth portion at the time of the webbing accelerating.
The vehicular seatbelt retractor may further comprise the pawl device for generating the repulsive force between the first permanent magnet on the upper portion of the standing weight and the second permanent magnet on the pawl lever according to the slanting ingredient of the standing weight and coupling the pawl lever with the second tooth portion, thereby enabling the detection of the abnormal state of the vehicle.